Subject: General Aptitude · Chapter: Time and Distance · Exam: 2006 · Marks: · Difficulty:
A fast train takes 3 hours less than a slow train for a journey of 600 km. If the speed of the slow train is 10 km/hr less than that of the fast train, then find the speeds of the two trains.
Answer
Answer (as printed):
Explanation
Let the speed of the fast train be x km/hr. The, speed of the slow train = (x – 10) km/hr. 600 600 \ – = 3 ⇔ 600 x – 600 (x – 10) = 3x (x – 10) ( x – 10) x ⇔ x2 – 10x – 2000 = 0 ⇔ x2 – 50x + 40x – 2000 = 0 ⇔ x(x – 50) + 40 (x – 50) = 0 ⇔ (x – 50) (x + 40) = 0 ⇔ x = 50. Hence, speed of fast train = 50 km/hr and speed of slow train = 40 km/hr. 3
Explanation as extracted from the printed page; notation may be imperfect.